The present invention relates to a rear vehicle-body structure which comprises a damper support portion to support a rear suspension damper and a frame member extending in a vehicle longitudinal direction, such as a rear side frame, wherein the frame member is configured to serve as the damper support portion.
As exemplified by Japanese Patent Laid-Open Publication No. 2003-137140, a rear vehicle-body structure in which a damper support portion (a suspension attachment portion (33)) to support a rear suspension damper (hereafter, referred to as a “damper”) is provided at a position located on an outward side, in a vehicle width direction, of a frame member (a rear side frame (7)) and on an inward side, in the vehicle width direction, of a wheel house inner (19) is known.
Herein, differently from the above-described structure of the patent document where the frame member, the damper support portion, and the wheel house inner are arranged along the vehicle width direction, it may be considered that a recessed portion 150 is formed at a frame member 160, wherein the recessed portion 150 is configured such that a lower face of the frame member 160 is recessed upwardly, and a damper (not illustrated) is inserted, from below, into and supported at a damper insertion hole 151 which is formed at a recessed bottom of the recessed portion 150, similarly to a rear vehicle-body structure 100 illustrated in FIG. 11.
In this case, however, outward-side and inward-side closed cross sections 160sa, 160sb are formed at a longitudinal position of the frame member 160 which corresponds to the recessed portion 150, wherein the closed cross sections 160sa, 160sb are configured to branch off from a closed cross section of the frame member 460 outwardly and inwardly, in the vehicle width direction, relative to the damper as shown in FIG. 12, a sectional view taken along line D-D of FIG. 11. Therefore, the branch-shaped closed cross sections have a smaller total area than the other portion of the frame member which does not correspond to the recessed portion 150, so that it is difficult to secure the modulus of section. In particular, when a rear-collision load is transmitted forwardly from a rear side of the frame member in a case where an obstacle collides with a vehicle rear portion (in a rear collision), it is required that the rear-collision load does not concentrate on the portion of the frame member 160 which corresponds to the recessed portion having the small modulus of section.